This new application seeks to test the involvement of the p53 protein in the evolution of prostate cancer to an androgen-independent state. Aim 1 is to determine the growth response to androgens of androgen-sensitive human prostate cell lines in vivo and in vitro. Aim 2 is to study the impact of inactivation of the p53 protein on growth responses to androgens in androgen-sensitive human prostate cancer cell lines. Aim 3 is to determine the effects of expressing a wild type p53 gene in androgen-insensitive prostate cancer cell lines lacking endogenous p53 protein.